Decorative sheet

ABSTRACT

The present invention improves a surface protective layer in the resistance to marring to the extent not achieved even if the surface protective layer is made of a crosslinked cured product of an ionizing radiation-curable resin and added with silica. When forming a layer comprising the crosslinked cured product of the ionizing radiation-curable resin as a surface protective layer ( 2 ) on a substrate sheet ( 1 ) made of paper or the like, fired kaolin is contained as a filler in the surface protective layer. The fired kaolin is preferably surface-treated with a silane coupling agent. On the substrate sheet ( 1 ), a wholly solid layer ( 3 ) and a pattern layer ( 4 ) are generally provided. A primer layer may be optionally provided between the substrate sheet and the surface protective layer.

TECHNICAL FIELD

The present invention relates to a decorative sheet such as a decorativepaper or the like, which can be used for: interior decoration materialfor buildings such as a wall or the like; and surface material forfittings such as a door, furniture or the like. Particularly, thepresent invention relates to a decorative sheet which has relatively lowchance of change in gloss due to surface damage and excellent resistanceto marring.

BACKGROUND ART

Conventionally, a decorative sheet using paper, resin sheet or the like,or a decorative material in a form of plate or the like wherein thedecorative sheet is applied to an adherend substrate has been used forvarious purposes such as an interior decoration material of building,fittings or the like. Also, such a decorative sheet or a decorativematerial to which the decorative sheet is applied usually requiressurface strength including surface hardness against damage or resistanceto abrasion. Thus, conventionally, a decorative sheet for such usesrequiring surface strength often has a structure wherein a surfaceprotective layer made of a crosslinked cured product such as twocomponent (two solution) curing type resin, ionizing radiation-curableresin or the like is provided on the whole surface.

However, although the crosslinked cured product of ionizingradiation-curable resin was used for the surface protective layer, therewere cases that surface damages were not sufficiently prevented. Inorder to deal with such cases, a filler such as silica or the like hasbeen generally added to the surface protective layer to harden thesurface protective layer. But still, particularly in the case of adecorative sheet a surface gloss of which is adjusted by a surfaceprotective layer for depicting design, gloss could increase due to acollection of very fine scratches. That is the case, for example, whenplural decorative plates respectively produced by applying a decorativesheet to a substrate of a wood plate or the like are piled up duringtransport and surfaces of the decorative plates (decorative sheets) arescratched by vibration, or when decorative plates are handled in aproduction line. It is still better if fine scratches are uniformlyfound on whole surface. But if just one part of a surface is frequentlyscratched, gloss on the surface becomes uneven and stands out resultingin a product defect. Particularly, there has been a problem that loss incost of a product defect found after a decorative sheet was applied to asubstrate is larger than that of solely a defect in a decorative sheetsince not only the decorative sheet but also the substrate becomesdefective. Therefore, it has been desired for a decorative sheet to haveresistance to marring so that it is less likely to change gloss even ifthe surface is rubbed.

DISCLOSURE OF INVENTION

Accordingly, an object of the present invention is to improve resistanceto marring of a decorative sheet such as a decorative paper or the like.

In order to attain the above object, a decorative sheet of the presentinvention has features so as to comprises a substrate sheet laminatedwith at least a surface protective layer comprising a crosslinked curedproduct of an ionizing radiation-curable resin, wherein the surfaceprotective layer contains fired kaolin as a filler.

By adding the fired kaolin as a filler in a surface protective layercomprising a crosslinked cured product of an ionizing radiation-curableresin as mentioned above, resistance to marring improves and becomesfavorable.

In addition to the above mentioned features, the fired kaolin for thedecorative sheet of the present invention is surface-treated with asilane coupling agent.

Thus, by adding fired kaolin which is surface-treated with a silanecoupling agent, resistance to marring further improves and becomesfavorable.

Also, a decorative sheet of the present invention in any of the abovefeatures further has a primer layer provided between a substrate sheetand a surface protective layer.

By providing the primer layer as above, adhesion between a surfaceprotective layer and a substrate sheet improves and peeling, chippingand defect of the surface protective layer are prevented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1(A) and FIG. 1(B) are sectional views respectively showing anexample of an embodiment of a decorative sheet of the present invention;and

FIG. 2 is a sectional view showing another example of an embodiment of adecorative sheet of the present invention.

The numerical symbol in each figure refers to the following: a substratesheet (1); a surface protective layer (2); a wholly solid layer (3); apattern layer (4); a penetration-inhibiting layer (5); a penetrablepattern layer (6), a concavo-convex layer (7); a decorative sheet (S).

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiment of the present invention will be hereinafter explainedwith reference to the drawings.

Outline:

Firstly, FIG. 1 is a sectional view showing a decorative sheet S of thepresent invention. FIG. 1(A) shows the most basic layer constitutioncomprising two layers, i.e. a substrate sheet 1 and a surface protectivelayer 2. FIG. 1(B) shows a constitution wherein a wholly solid layer 3and a pattern layer 4 are provided in this order on the substrate sheet1 between the substrate sheet 1 and the surface protective layer 2 asdecoration treatment. The surface protective layer 2 is made of acrosslinked cured product of ionizing radiation-curable resin, and firedkaolin is added as a filler. The present invention has found out thatresistance to marring improves if fired kaolin is used as a fillerinstead of just an ordinary kaolin.

A decorative sheet of the present invention may be comprised of twolayers, i.e. a substrate sheet 1 and a surface protective layer 2, asshown in FIG. 1(A). However, a constitution of a decorative sheetusually has some decoration treatment to improve design as shown in FIG.1(B). Generally, the decoration treatment is applied to the substratesheet. A substrate sheet may be a resin sheet. If a substrate sheet ismade of paper or the like, such a decorative sheet may be called as adecorative paper.

Hereinafter, the present invention will be explained in detail for eachlayer in order.

Substrate Sheet:

As a substrate sheet 1, there may be used papers, nonwoven fabrics,thermoplastic resin sheets, laminates thereof or the like.

As papers, there may be used tissue papers, kraft papers, wood freepapers, linter papers, baryta papers, parchment papers, Japanese papersor the like.

As nonwoven fabrics, there may be used nonwoven fabrics made from fibersmade of polyester resin, acrylic resin, nylon, vinylon, glass or thelike. Papers and nonwoven fabrics generally have a basis weight of about20 to 100 g/m². Further, in order to intensify strength between fibersor layers and prevent fuzz, a resin such as acrylic resin,styrene-butadiene rubber, melamine resin, urethane resin or the like maybe further added to papers or nonwoven fabrics (the resin is impregnatedafter making paper or filled inside while making paper).

A decorative sheet using a paper (or a nonwoven fabric) as a substratesheet becomes a decorative paper.

As thermoplastic resin sheets, there may be used acrylic resins,polyester resins, polyolefin based resins, polyvinyl chloride resins,polystyrene, ABS resins, polycarbonate resins, polyamide resins or thelike.

Specifically, for example, (1) polyolefin resins such as polyethylene(high, medium, or low density), polypropylene (isotactic type orsyndiotactic type), polybutene, ethylene-propylene copolymer,ethylene-propylene-butene copolymer, olefin based thermoplasticelastomer or the like. The olefin based thermoplastic elastomer iscomprised of a mixture of a hard segment including crystallinepolyolefin resin as exemplified above and a soft segment includingelastomer such as ethylene-propylene rubber, ethylene-propylene-dienerubber, atactic polypropylene, styrene-butadiene rubber, hydrogenatedstyrene-butadiene rubber or the like. The mixing ratio of the hardsegment and the soft segment is approximately (soft segment/hardsegment)=5/95 to 40/60 (mass ratio). As required, the elastomercomponent is crosslinked by a well-known crosslinking agent such assulfur, hydrogen peroxide or the like.

(2) Acrylic resins such as polymethyl(meth)acrylate,polybutyl(meth)acrylate, methyl(meth)acrylate-butyl(meth)acrylatecopolymer, methyl(meth)acrylate-styrene copolymer or the like (herein,(meth)acrylate refers to acrylate or methacrylate).

(3) Polyester resins such as polyethylene terephthalate, polybutyleneterephthalate, ethylene-terephthalate isophthalate copolymer,polyethylene naphthalate, polyester based thermoplastic elastomer,amorphous polyester or the like. As the polyester based thermoplasticelastomer, there may be a blockpolymer using highly crystalline aromaticpolyesters having high melting point as the hard segment and amorphouspolyether having a glass transition temperature of −70° C. or less asthe soft segment. As the highly crystalline aromatic polyesters havinghigh melting point, there may be used polybutylene terephthalate. As theamorphous polyether, there may be used polytetramethylene glycol or thelike. A typical example of the amorphous polyester isethyleneglycol-1,4-cyclohexanedimethanol-terephthalic acid copolymer.

(4) As other resins, there may be polycarbonate resin, polyvinylchloride resin, polyamide resin, polyphenylene sulfide, polyether etherketone or the like.

The layer constitution of the substrate sheet may be a single layerusing said paper, nonwoven fabric, thermoplastic resin sheet or the likeor two or more layers using different kinds. The thickness (totalthickness in the case of a laminate) of the substrate sheet is normallyabout 25 to 500 μm.

Surface Protective Layer:

A surface protective layer 2 is formed as the outermost surface layer ofa decorative sheet by using an ionizing radiation-curable resin andcuring the resin by crosslinking to be a crosslinked cured product.Firstly, the use of the ionizing radiation-curable resin as the resin ofthe surface protective layer makes it easier to impart wear resistancesuch as resistance to marring or the like or surface properties such asresistance to staining or the like due to high crosslinking ability ofthe ionizing radiation-curable resin compared to the case using twocomponent curing type urethane resin or the like. Secondly, fired kaolinis added as a filler in the surface protective layer. Thereby,resistance to marring improves.

The surface protective layer is usually formed as an uncoloredtransparent layer or a colored transparent layer in order to have apattern layer generally provided on the underside of the surfaceprotective layer see through. However, if it is not necessary to havethe pattern layer see through in such a case that there is no patternlayer or the like, the surface protective layer may be an uncoloredopaque layer or a colored opaque layer.

The surface protective layer can be formed in such manner that theionizing radiation-curable resin (composition) in which fired kaolin iscontained and liquidized is applied on a substrate sheet by aconventional layer forming method including coating methods such asgravure coating, roll coating or the like, or printing methods such asgravure printing, gravure offset printing, screen printing or the like,and thereafter irradiating it with an ionizing radiation to cure bycrosslinking. The thickness of the surface protective layer is generallyabout 1 to 30 g/m² (based on solid content) in coating amount. Solventsare accordingly added to the ionizing radiation-curable resin(composition) for adjustment of coatability, printability or the like.

As the ionizing radiation-curable resin, there may be preferably used acomposition which is curable by crosslinking with ionizing radiation andcomprised of a suitable mixture of prepolymers (so called oligomers areincluded) and/or monomers, each of which has a radically polymerizableunsaturated bond(s) or a cationically polymerizable functional group(s)in the molecule thereof. Ionizing radiation used herein refers toelectromagnetic radiations or charged particle beams which have energyquanta capable of polymerizing and crosslinking molecules. Generally,ionizing radiation refers to electron beam (EB) or ultraviolet light(UV).

The prepolymer or monomer may be a compound having a radicallypolymerizable unsaturated group such as a (meth) acryloyl group, (meth)acryloyloxy group or the like, a cationically polymerizable functionalgroup such as epoxy group or the like in the molecule thereof. Theprepolymer and monomer may be used solely or in mixture of plural kinds.Herein, for example, a (meth)acryloyl group refers to an acryloyl groupor a methacryloyl group. As the ionizing radiation-curable resin, theremay be preferably used a polyene/thiol based prepolymer, which is acombination of polyene and polythiol.

As examples of the prepolymer having a radically polymerizableunsaturated group in the molecule thereof, there may be usedpolyester(meth)acrylate, urethane(meth)acrylate, epoxy(meth)acrylate,melamine(meth)acrylate, triazine(meth)acrylate or the like. Generally,prepolymers having molecular weight of about 250 to 100,000 are used.The term, (meth)acrylate used herein refers to acrylate or methacrylate.A acrylate compound and a methacrylate compound may be named genericallyand simply referred as acrylate (compound).

Examples of the monomer having radically polymerizable unsaturated groupin the molecule thereof are monofunctional monomers such asmethyl(meth)acrylate, 2-ethylhexyl(meth)acrylate,phenoxyethyl(meth)acrylate or the like, and polyfunctional monomers suchas diethyleneglycoldi(meth)acrylate, propyleneglycoldi(meth)acrylate,trimethylolpropanetri(meth)acrylate,trimethylolpropaneethyleneoxidetri(meth) acrylate,dipentaerythritoltetra(meth)acrylate,dipentaerythritolpenta(meth)acrylate,dipentaerythritolhexa(meth)acrylate or the like.

Examples of the prepolymer having cationically polymerizable unsaturatedgroup in the molecule thereof are epoxy resins such as bisphenol epoxyresins, novolak epoxy compounds or the like, vinyl ether resins such asfatty acid vinyl ether, aromatic vinyl ether or the like.

As thiol, there may be polythiol such as trimethylolpropanetrithioglycolate, pentaerythritoltetrathioglycolate or the like. Aspolyene, there may be polyurethane comprising diol and diisocyanate withallyl alcohol added on both ends.

In order to cure by crosslinking using ultraviolet ray, a photopolymerization initiator is added to the ionizing radiation-curableresin. In the case of resins having radically polymerizable unsaturatedgroup, acetophenones, benzophenones, thioxanthones, benzoins orbenzoinmethyl ethers may be used solely or in mixture thereof as thephoto polymerization initiator. In the case of resins havingcationically polymerizable functional group, aromatic diazonium salt,aromatic sulfonium salt, aromatic iodonium salt, metallocene compound,benzoin sulfonic ester or the like may be used solely or in mixturethereof as the photo polymerization initiator.

The amount of the photo polymerization initiator added ranges from about0.1 to 10 parts by mass to 100 parts by mass of the ionizingradiation-curable resin.

Further to the ionizing radiation-curable resin besides the aboveresins, if necessary, ionizing radiation non-curing resins may be added,for instance, thermoplastic resins such as vinyl chloride-vinyl acetatecopolymer, vinyl acetate resin, acrylic resin, cellulose resins or thelike.

The fired kaolin is obtained by firing commonly used (hydro) kaolin. Byadding fired kaolin as a filler, improvement in resistance to marringwhich has not been achieved by silica or unfired hydrokaolin isattained. A particle diameter of fired kaolin powder may be selectedaccording to uses, required physical properties or the like. Forexample, fired kaolin having an average particle diameter of about 0.5to 2 μm may be used. The amount of fired kaolin added may be selectedaccording to uses, required physical properties or the like For example,the amount of fired kaolin added may be about 5 to 50 parts by massbased on 100 parts by mass of an ionizing radiation-curable resin (atotal amount of an ionizing radiation-curable resin and other binderresins if a surface protective layer further contains other binderresins).

A refractive index of fired kaolin approaches that of the resin of thesurface protective layer when the refractive index of fired kaolin iswithin the range of 1.6 to 1.7, particularly at 1.65, a center valuethereof (a refractive index of hydrokaolin is 1.56), thus, using firedkaolin is advantageous in terms of transparency of the surfaceprotective layer. Also, fired kaolin is superior in coating stability tohydrokaolin.

As fired kaolin, there may be used a fired kaolin in which its surfaceis further subjected to surface treatment. By using the surface-treatedfired kaolin, the effect of improvement in resistance to marring can befurther increased. The surface treatment may be that using a silanecoupling agent.

As the silane coupling agent, there may be well known silane couplingagents containing alkoxy group, amino group, vinyl group, epoxy group,mercapto group, chloride group or the like.

For example, there are γ-aminopropyltriethoxy silane,γ-methacryroxypropyltrimethoxy silane, γ-methacryroxypropylmethyldimethoxy silane, γ-methacryroxypropyldimethylmethoxy silane,γ-methacryroxypropyltriethoxy silane, γ-methacryroxypropyldimethylethoxysilane, γ-acryroxypropyltrimethoxysilane,γ-acryroxypropylmethyldimethoxy silane, γ-acryroxypropyl dimethylmethoxysilane, γ-acryroxypropyltriethoxy silane, γ-acryroxypropylmethyldiethoxysilane, γ-acryroxypropyl dimethylethoxysilane, vinyltriethoxy silane,γ-glycidoxypropyl trimethoxy silane, γ-mercaptopropyltrimethoxy silaneor the like.

To the surface protective layer, other well-known additives may beaccordingly added, for instance, lubricants such as silicone resin, waxor the like, colorants, stabilizing agents, fungicides or the like asrequired.

As a source of electron beam for the ionizing radiation, there may beused various electron beam accelerators such as Cockcroft-Walton type,Van de Graaff type, resonance transformer type, isolation coretransformer type, linear type, Dynamitron type, high frequency type orthe like, which radiates electron having energy quantum of 100 to 1000keV, preferably 200 to 300 keV. As a source of the ultraviolet ray,there may be used an ultrahigh-pressure mercury-vapor lamp, ahigh-pressure mercury-vapor lamp, a low-pressure mercury-vapor lamp, acarbon-arc lamp, a black light, a metal halide lamp or the like.

Design Treatment:

A constitution of a decorative sheet may be simply two layers comprisedof a substrate sheet and a surface protective layer or may have a primerlayer made of two component curing type urethane resin or the likebetween the substrate sheet and the surface protective layer forincreasing adhesion. However, a constitution of the decorative sheetgenerally is to be subjected to some decoration treatment in order toincrease design effect. Even in the case of a decorative sheet mainlycomprised of a substrate sheet and a surface protective layer, it ispossible to apply decoration treatment. For example, if the substratesheet is a resin sheet, decoration treatment may be applied by addingcolorant to the resin sheet, by using a colored paper, or by adding acolorant to the surface protective layer or the like. However, it is notcapable of presenting advanced design by printed pattern or the like,thus, a pattern layer or the like is generally provided for exhibitingadvanced design. There is no particular limit in contents of thedecoration treatment. Various conventional decoration treatments in thefield of a decorative sheet may be adopted accordingly. Hereinafter, asexamples of the decoration treatment, a pattern layer, a wholly solidlayer and formation concavo-convex pattern on a surface will beexplained.

[Pattern Layer]

A pattern layer 4 is a layer for exhibiting design formed by partialprinting in a form of pattern. It is preferable to provide the patternlayer as an inner layer of a decorative sheet in view of durability ofpattern. Hence, the pattern layer is located between a substrate sheetand a surface protective layer, and generally formed on an upper sidesurface of the surface sheet.

Upon providing the pattern layer, there is no particular limit incontents of the pattern layer such as a method of forming the patternlayer, materials, design or the like, and may be according to the uses.The pattern layer is usually formed using an ink by a conventionalprinting method or the like such as gravure printing, silk screenprinting, offset printing, gravure offset printing, ink jet printing orthe like.

Patterns of the pattern layer include, for example, woodgrain patterns,rift patterns, sand grain patterns, texture patterns, tile patterns,brick patterns, leather grain patterns, letters, symbols, geometricfigures, or a combination of two or more kinds thereof.

The ink used for forming the pattern layer is comprised of vehiclesincluding binders or the like, colorants such as pigments, dyes or thelike, various additives added accordingly such as extenders, stabilizingagents, plasticizers, catalysts, curing agents or the like. A resin ofthe binders may be selected from thermoplastic resins, thermosettingresins, ionizing radiation-curable resins or the like according to therequired physical properties, printability or the like. For example,cellulose resins such as cellulose nitrate, cellulose acetate, celluloseacetate propionate or the like; acrylic resins such as polymethyl(meth)acrylate, polybutyl (meth)acrylate, methyl (meth)acrylate-butyl(meth)acrylate-2-hydroxyethyl (meth)acrylate copolymer or the like;urethane resins; vinyl chloride-vinyl acetate copolymer; polyesterresins; alkyd resins or the like may be used solely or as a mixturecontaining thereof for the resin of the binder.

The colorants usable herein include: inorganic pigments such as titaniumwhite, carbon black, iron black, red iron oxide, chrome yellow,ultramarine blue or the like; organic pigments such as aniline black,quinacridone red, isoindolinone yellow, phthalocyanine blue or the like;luster pigments such as flake powders of titanium dioxide covered mica,aluminum or the like; or other dyes.

[Wholly Solid Layer]

A wholly solid layer 3 is a layer formed on whole surface between asubstrate sheet and a surface protective layer, which may be solelyprovided not in combination with the aforementioned pattern later 4,however, generally, it is often used as an undercoat of the patternlayer 4 in combination with the pattern later 4.

When providing the wholly solid layer, there is no particular limit informing methods, materials or the like of the wholly solid layer, whichmay be selected according to the uses. The wholly solid layer is formedusing an ink or a coating liquid by a conventional printing method suchas gravure printing, silkscreen printing, offset printing, gravureoffset printing, ink jet printing or the like, or a conventional coatingmethod such as gravure coating, roll coating or the like. The thicknessof the wholly solid layer is generally about 1 to 10 g/m² (based onsolid content) in coating amount.

There are various purposes to provide the wholly solid layer 3, forinstance, achieving one or more functions among (1) exhibiting a basecolor, (2) imparting hiding properties, (3) inhibiting penetration orthe like. (1) Exhibiting a base color generally refers to rendering anundercoat color for pattern coloration of a pattern layer. (2) Impartinghiding properties refers to stabilizing coloration of a decorative sheetby hiding unevenness of color tone between lots in the case of asubstrate sheet using paper or a colored resin sheet, or stabilizingexhibition of coloration or pattern of a decorative sheet by hiding anadherend substrate in the case of a substrate sheet using a transparentresin sheet or the like. (3) Inhibiting penetration refers to preventinggeneration of gloss unevenness or the like on a surface of a surfaceprotective layer by inhibiting an ink or a coating liquid frompenetrating to a substrate sheet upon forming a pattern layer, thesurface protective layer or the like in the case of a penetrablesubstrate sheet such as paper or the like. Among these functions, (1)and (2) are decoration treatment. The wholly solid layer of the presentinvention includes embodiments solely for the use directed to a purposeother than the decoration treatment such as (3).

The wholly solid layer functions variously as mentioned above accordingto the uses, wherein same materials as the ink materials described inthe aforementioned patter layer can be used. Thus, detailed explanationon a resin of a binder or the like is hereby omitted. In order toexhibit a base color or impart hiding properties, various colorants suchas titanium white or the like listed in the aforementioned pattern layermay be added, however, in terms of inhibiting penetration, it is notnecessary to add a colorant for the purpose of coloring.

[Forming Concavo-Convex Pattern on a Surface]

Forming a concavo-convex pattern on a surface is a decoration treatmentto form a concavo-convex pattern on a surface of a surface protectivelayer. The effect of improvement in resistance to marring according tothe present invention can be obtained even if there is a concavo-convexpattern on a surface of a decorative sheet, for instance, aconcavo-convex pattern like a concavo-convex pattern of woodgrain vesselgrooves wherein convex portions other than concave portions comprise aflat surface and function as a gloss regulating surface. In this case,the resistance to marring is resistance against change in gloss of theflat surface (convex portions) from the view point of the micro level.

The change in gloss of a surface covered by the resistance to marringgenerally includes increase of gloss in the case that surface gloss isappropriately decreased to adjust gloss (i.e. medium gloss) as a design,that is, appearance of gloss as the result of deterioration of the matteeffect of the surface. However, change in gloss covered by theresistance to marring also includes decrease in gloss as well asincrease in gloss.

As the concavo-convex pattern, a pattern is employed according to theuses, for instance, woodgrain vessel grooves, joint grooves of tilelaying or bricklaying, relief patterns, letters, symbols, geometricfigures, satin finished surfaces, concavo-convex patterns on cleavageplane of granite or the like. The concavo-convex pattern may be acombination of these patterns.

As an example of the decoration treatment for forming the concavo-convexpattern such as woodgrain vessel grooves or the like on a surface, thereis a technique to form a concavo-convex pattern by providing apenetrable hill-and-dale pattern as an undercoat prior to forming asurface protective layer using a coating liquid (or an ink) for forminga surface protective layer (see FIG. 2 and Japanese Patent ApplicationLaid-Open (JP-A) No. 2001-328228 or the like). For example, a penetrablepattern layer 6 in a pattern form is formed by accordingly providing awholly solid layer 3 and a pattern layer 4 on a substrate sheet 1,forming a penetration-inhibiting layer 5 by coating a resin liquid onwhole surface, and printing an ink in which a filler such as silica orthe like is added in order to impart penetration. The penetrable patternlayer is, for instance, a layer accordingly depicting a design of aconcavo-convex pattern such as a vessel groove pattern or the like. Acoating liquid for forming a surface protective layer may be coated onwhole surface of the penetrable pattern layer, thereby, the coatingliquid on the upper part of the penetrable pattern layer 6 penetratesinto inside of the penetrable pattern layer. However, the coating liquidon the upper part of the penetration-inhibiting layer 5 does notpenetrate into inside of the penetration-inhibiting layer. Therefore, aconcavo-convex pattern 7 having a concave on every penetrable patternlayer 6 is formed on the surface of the surface protective layer 2.According to the concavo-convex pattern forming technique, inside of theformed concave of the concavo-convex pattern 7 can be a rough surface,thus, it is possible to render a design using differences of glossbetween convex portions and portions (see FIG. 2).

Primer Layer:

A primer layer is provided preferably between a surface protective layerand a substrate sheet in the case that the strengthening of inter-layeradhesion between the surface protective layer and the substrate sheet isnecessary. The location for forming the primer layer is, for instance,if there is a pattern layer between a substrate sheet and a surfaceprotective layer, the location of the primer layer is between thepattern layer and the surface protective layer or the like.

As the primer layer, a resin such as urethane resins, acrylic resins,polyvinyl butyral or the like may be used solely or in mixture of one ormore kids thereof. The primer layer is formed using a coating liquid (oran ink) made of the above resin by a conventional coating method such asgravure coating, roll coating or the like, or a conventional printingmethod such as gravure printing or the like. The thickness of the primerlayer is generally about 0.5 to 5 g/m² (based on solid content) incoating amount.

Adherend Substrate:

A decorative sheet of the present invention may be used as a decorativematerial such as a decorative plate by applying the decorative sheet toa surface of various adherend substrates.

There is no particular limitation to the adherend substrate. Forexample, material of the adherend substrate may be inorganic nonmetals,metals, woods, plastics or the like. Specifically, as nonmetals, theremay be non-pottery ceramic materials such as paper-making cement,extrusion cement, slag cement, ALC (aerated lightweight concrete), GRC(glass fiber-reinforced concrete), pulp cement, wood chip cement,asbestos cement, calcium silicate, gypsum, gypsum slag or the like; orinorganic materials such as ceramics such as biscuit wares,earthenwares, porcelains, stonewares, glass, porcelain enamels or thelike. As metals, there may be metal materials such as iron, aluminum,copper or the like. As woods, there may be veneers, plywoods, particleboards, fiber boards, laminated woods or the like made of cedar,cypress, oak, lauan, teak or the like. As plastics, there may be resinmaterials such as polypropylene, ABS resin, phenolic resin or the like.

The form of the adherend substrate may be a flat plate, a curved plate,a polygonal prism or the like.

Application:

The use of a decorative sheet of the present invention may notparticularly be limited. The decorative sheet may be used for interiordecoration material of buildings for walls, ceilings or the like;surface materials for fittings such as doors, doorframes, window framesor the like; surface materials for furnishings materials such as roundedges, plinths or the like; or surface materials for furniture such aschests, cabinets or the like by applying to a surface of the adherendsubstrate as mentioned above.

EXAMPLE

Hereinafter, the present invention will be explained in more detail withexamples and comparative examples.

Example 1 Fired Kaolin

A wholly solid layer 3 and a pattern layer 4 were successively formed ona substrate sheet 1 made of a tissue paper for building materials(general paper grade, a basis weight of 30 g/m²) by gravure printing,wherein the wholly solid layer 3 is white color, has hiding properties,and contains acrylic resin as a binder resin and titanium oxide as acolorant, and wherein the pattern layer 4 has woodgrain design, andcontains nitrocellulose resin as a binder resin and a colorant. Next, onthe laminate thus obtained, an electron beam-curable resin coatingliquid of the composition mentioned below was applied by a gravureoffset method. Then, the coating layer was irradiated with an electronbeam to be cured by crosslinking, thereby, a surface protective layer 2,which is colorless and transparent and has thickness of 4 g/m², wasformed to obtain a decorative sheet S as shown in the cross-sectionalview of FIG. 1(B).

Composition of Electron Beam-Curable Resin Coating Liquid: Acrylatetrifunctional monomer  50 parts by mass Acrylate bifunctional monomer 30 parts by mass Silicone methacrylate 0.6 parts by mass Fired kaolin(average particle size 0.8 μm)  30 parts by mass

Example 2 Fired Kaolin (Surface-Treated Type)

Except that the composition of the electron beam-curable resin coatingliquid for forming a surface protective layer was changed to thecomposition mentioned below, wherein a surface-treated fired kaolin wasadded, a decorative sheet was produced in the same manner as Example 1.

Composition of Electron Beam-Curable Resin Coating Liquid: Acrylatetrifunctional monomer  50 parts by mass Acrylate bifunctional monomer 30 parts by mass Silicone methacrylate 0.6 parts by mass Fired kaolin(average particle size 0.8 μm,  30 parts by mass surface-treated bysilane coupling agent)

Example 3 Fired Kaolin, Concavo-Convex Pattern

A wholly solid layer 3, a pattern layer 4, a penetration-inhibitinglayer 5 and a penetrable layer 6 were successively formed on a substratesheet 1 made of a tissue paper for building materials (general papergrade, a basis weight of 30 g/m²) by gravure printing, wherein thewholly solid layer 3 is white color, has hiding properties, and containsacrylic resin as a binder resin and titanium oxide as a colorant,wherein the pattern layer 4 has woodgrain design, and containsnitrocellulose resin as a binder resin and a colorant, wherein thepenetration-inhibiting layer 5 is comprised of a mixed resin of urethaneresin and polyester resin, and wherein the penetrable layer 6 has awoodgrain vessel pattern consistent with a vessel portion in design ofthe pattern layer, contains urethane resin as a binder resin, and isadded with silica. Next, on the laminate thus obtained, an electronbeam-curable resin coating liquid of the composition mentioned below wasapplied by a gravure offset method. Then, the coating layer wasirradiated with an electron beam to be cured by crosslinking, thereby, asurface protective layer 2, which is colorless and transparent and hasthickness of 4 g/m², is formed to obtain a desired decorative sheet Shaving a surface with a concavo-convex pattern 7 of a vessel groovepattern consistent with a woodgrain design of the pattern layer as shownin the cross-sectional view of FIG. 2.

Composition of Electron Beam-Curable Resin Coating Liquid: Acrylatetrifunctional monomer  50 parts by mass Acrylate bifunctional monomer 30 parts by mass Silicone methacrylate 0.6 parts by mass Fired kaolin(average particle size 0.8 μm)  30 parts by mass

Comparative Example 1 No Kaolin, Silica

Except that the composition of the electron beam-curable resin coatingliquid for forming a surface protective layer was changed to thecomposition mentioned below, wherein silica was added instead of firedkaolin, a decorative sheet was produced in the same manner as Example 1.

Composition of Electron Beam-Curable Resin Coating Liquid: Acrylatetrifunctional monomer  50 parts by mass Acrylate bifunctional monomer 30 parts by mass Silicone methacrylate 0.6 parts by mass Silica(average particle size 6 μm)  30 parts by mass

Comparative Example 2 Hydrokaolin

Except that the composition of the electron beam-curable resin coatingliquid for forming a surface protective layer was changed to thecomposition mentioned below, wherein ordinary hydrokaolin was addedinstead of fired kaolin, a decorative sheet was produced in the samemanner as Example 1.

Composition of Electron Beam-Curable Resin Coating Liquid: Acrylatetrifunctional monomer  50 parts by mass Acrylate bifunctional monomer 30 parts by mass Silicone methacrylate 0.6 parts by mass Hydrokaolin(average particle size 0.6 μm)  30 parts by mass

Comparative Example 3 Without Filler

Except that the composition of the electron beam-curable resin coatingliquid for forming a surface protective layer was changed to thecomposition mentioned below, wherein fired kaolin was not added and afiller was not contained, a decorative sheet was produced in the samemanner as Example 1.

Composition of Electron Beam-Curable Resin Coating Liquid: Acrylatetrifunctional monomer  50 parts by mass Acrylate bifunctional monomer 30 parts by mass Silicone methacrylate 0.6 parts by mass

Example 4 Resin Sheet/Fired Kaolin

A wholly solid layer 3 and a pattern layer 4 were successively formed ona substrate sheet 1 made of a polypropylene resin sheet, which is whitecolor, has hiding properties and has thickness of 80 μm, by gravureprinting, wherein the wholly solid layer 3 is white color, has hidingproperties, and contains urethane resin as a binder resin and titaniumoxide as a colorant, and wherein the pattern layer 4 has woodgraindesign, and contains urethane resin as a binder resin and a colorant.Next, on the laminate thus obtained, an electron beam-curable resincoating liquid of the composition mentioned below was applied by gravureoffset method. Then, the coating layer was irradiated with an electronbeam to be cured by crosslinking, thereby, a surface protective layer 2,which is colorless and transparent and has thickness of 4 g/m², isformed to obtain a desired decorative sheet S as shown in thecross-sectional view of FIG. 1(B).

Composition of Electron Beam-Curable Resin Coating Liquid: Acrylatetrifunctional monomer  50 parts by mass Acrylate bifunctional monomer 30 parts by mass Silicone methacrylate 0.6 parts by mass Fired kaolin(average particle size 0.8 μm)  30 parts by mass[Evaluation of Performances]

Resistance to marring of each decorative sheet formed in Examples andComparative examples was evaluated. The resistance to marring wasevaluated by visually observing state of change in gloss of a surface ofthe decorative sheet after a rubbing test (resistance to steel wooltest), wherein the surface of the decorative sheet is rubbed for 20times reciprocating motion with the use of a steel wool (BONSTARmanufactured by Nippon Steel Wool Co., Ltd.) which is fixed to a weightloading with 21014 Pa (1.5 kgf/7 cm²). The results are shown in Table 1.In the table, “⊚” refers to “excellent” without change in gloss, “◯”refers to “good” with small change in gloss, “x” refers to “not good”with change in gloss of the surface, and “xx” refers to “not good (outof the question)” with a pattern layer under the surface even rubbed.TABLE 1 Results of Performance Evaluation Filler Resistance to marringExample 1 Fired kaolin ◯: small change in gloss Example 2Surface-treated ⊚: no change in gloss fired kaolin Example 3 Firedkaolin ◯: small change in gloss Example 4 Fired kaolin ◯: small changein gloss Comparative Silica X: change in gloss Example 1 ComparativeHydrokaolin X: change in gloss Example 2 Comparative None XX: defectdown to a pattern Example 3 printing layer

As shown in Table 1, the performance of each example, wherein firedkaolin was added to a surface protective layer, was good or excellentthough some examples had change in gloss of the surface but the changewas small. Among them, the performance of the example having firedkaolin with surface-treatment was excellent without showing any changein gloss. To the contrary, the performance of each Comparative example,wherein fired kaolin was not added even though silica or the like wasadded, was not good including Comparative example 2, wherein hydrokaolinwas added.

Industrial Applicability

(1) According to a decorative sheet of the present invention, resistanceto marring improves. For example, though depending on the constitutionof a decorative sheet, the resistance to marring can be improved to theextend that change in gloss is small or ideally no change in gloss isobserved when a surface of a decorative sheet is visually observed aftera rubbing test as shown in examples, wherein the surface of thedecorative sheet is rubbed for 20 times reciprocating motion by a steelwool (BONSTAR manufactured by Nippon Steel Wool Co., Ltd.) which isfixed to a weight loading 14009 to 42028 Pa (1 to 3 kgf/7 cm²).

(2) Further, if a surface-treated fired kaolin is used in a surfaceprotective layer, resistance to marring is more improved and becomesmore preferable.

(3) Even further, by providing a primer layer between a substrate sheetand a surface protective layer, adhesion between the surface protectivelayer and the substrate sheet improves so that peeling, chipping, defector the like does not occur in the surface protective layer.

1. A decorative sheet comprising a substrate sheet laminated with atleast a surface protective layer comprising a crosslinked cured productof an ionizing radiation-curable resin, wherein the surface protectivelayer contains fired kaolin as a filler.
 2. A decorative sheet accordingto claim 1, wherein the fired kaolin is surface-treated with a silanecoupling agent.
 3. A decorative sheet according to claim 1, wherein aprimer layer is provided between the substrate sheet and the surfaceprotective layer.